These studies are designed to investigate a variety of renal physiological and pathophysiological phenomena. Micropuncture and microperfusion techniques are used in the rat to study factors which influence proximal tubular and loop reabsorption, especially the influence of peritubular oncotic and hydrostatic pressures (physical factors). In the dog clearance, studies are employed to study the interrelations between renal oxygen consumption and overall tubular transport of sodium under conditions where the transport of sodium has been manipulated experimentally. Another series of studies deals with the control of renin release in the dog. The influence of pH of the renal blood on renin release will be investigated and in other experiments the influence of exercise on renin release and the associated cardiovascular changes will be examined. In an unrelated project, the significance of antibody-coating of urinary bacteria in terms of the site of infection is under investigation in a large series of patients.